How to calculate FOV?

Question

Initial Context

I am developping an augmented reality application location based and I need to get the field of view [FOV] (I just update the value when the orient

Answer 1

In iOS 7 and above you can do something along these lines:

float FOV = camera.activeFormat.videoFieldOfView;

where camera is your AVCaptureDevice. Depending on what preset you choose for the video session, this can change even on the same device. It's the horizontal field-of-view (in degrees), so you'll need to calculate the vertical field-of-view from the display dimensions.

Here's Apple's reference material.